Adoptio had some commonalities with
emancipatio, the procedure by which an adult son was released from paternal
potestas – regardless of age, Roman men and women remained in effect legal
minors as long as their father was alive unless emancipated. The father's relinquishing of
potestas over the son in both cases took the form of a
fictive sale, based on an archaic provision of the
Twelve Tables (mid-5th century BC) that a son sold three times was thereafter released from his father's legal control.
Adrogatio Adrogatio differed from
adoptio in that the person adopted was already
sui iuris; another father did not have to surrender his
potestas, and rather than extirpating the adoptee's previous family line, the two family lines were merged. An adrogated adoptee was likely to have inherited from the natural father whose death had left him
sui iuris, consolidating two patrimonies. Ownership of anything belonging to the adoptee was legally transferred to the
paterfamilias, though it was set aside as
peculium, a fund or property for use by an unemancipated son or slave. When
Tiberius was adopted in adulthood by
Augustus, he thereafter observed this longstanding legal requirement by crediting any property he received through inheritance to the
peculium rather than his private ownership. The development of
adrogatio as a form of adoption is bound up with an early procedure for making a will that required the approval of the
comitia calata, an assembly of the Roman people. Upon the testator's death, the named heir was in effect adopted by the deceased. The legislative act of adrogation was carried out by thirty magisterial
lictors summoned by the
Pontifex Maximus. Because adoption law developed to support the particular institutions of Roman society,
adrogatio could take place only in the city of Rome until the reign of
Diocletian in the late third century. Adrogation of female adoptees became possible through imperial
rescript in the
Antonine era (AD 138–192), and under exceptional circumstances a woman could adopt in the same way. In one documented case from the 3rd century, a woman whose sons had died was permitted to adopt her stepson. Since a woman did not transfer paternal
potestas, however, adoption accomplished little that could not be achieved through exercising her rights under inheritance law.
Testamentary adoption as a child Testamentary adoption became more common during the late Republic. Octavian, the future Augustus, was adopted in this way by his maternal great-uncle
Julius Caesar. Although
adoptio was a practice aimed at furthering the succession of male privileges, both men and women could in effect "adopt" by passing along their property in a will with the condition that the heir carry on the family name
(condicio nominis ferendi). The role of women in passing property along the family line became "increasingly important". Technically, this was not adoption but the "institution of an heir." The advantage of this arrangement was that the testator did not have to assume patriarchal responsibilities for the adoptee while he was alive but had assured the continuity of the family name, rites, and estate after his death; the testamentary adoptee did not surrender his own status as a
pater as he would in adrogation but received the benefits of inheritance. Adoption was also the means by which married women could become part of their husband's family. From the late Republic through the Principate, most Roman women
married sine manu, meaning that they remained part of their birth family and did not submit to their husband's
potestas.
Livia, the wife of Augustus, outlived him, and only upon his death did testamentary adoption make her a part of the Julian family.
Legitimation Illegitimacy does not appear to have carried much stigma in Roman society before the time of
Constantine I, as many forms of
Roman marriage existed, some rather loosely defined, along with quasi-marital unions such as
contubernium among slaves and monogamous concubinage
(concubinatus). Birth outside marriage was primarily at issue in matters of inheritance but was not a clearly defined status with debilities in law, as a principle of customary international law
(ius gentium) was that a child took its status from the mother. A
freedwoman whose male partner remained enslaved might find it advantageous to assert that her child was fatherless and not conceived during her own servitude, so as to ensure the child's freeborn status. It was unusual for freeborn persons to legitimate a child born outside a legally valid marriage, and typically a man would not adopt his illegitimate child unless he had no other heirs. The adoptee could be
ingenuus (freeborn) or a freedman, and might be a child resulting from
concubinatus, though
children were not especially desired from these unions. Provisions for retroactive legitimation became more capacious in
late antiquity as family law was adapted during the
Christianization of the Roman Empire, in particular under Constantine and
Justinian. In the Classical period, legitimation might have been more common among former slaves. Since slaves lacked
personhood under Roman law, they could neither contract a valid marriage nor institute an heir by means of a will. However, the quasi-marital union of
contubernium was available to heterosexual slave couples with the owner's approval, and expressed an intent to marry if both parties gained rights of marriage and succession upon manumission. Because a male slave did not possess the standing to assert patriarchal
potestas, the child of an enslaved father was
spurius, one whose father could not be legally identified as such—that is, illegitimate. Since the child's status was determined by the mother's, if a woman was manumitted before her partner and conceived a child with him after that, the child was
spurius but freeborn; unlike freeborn children from a legal marriage, however, the child was born
sui iuris, emancipated from the
potestas of an adult male. If the father was later manumitted through a procedure that granted him full citizenship, he could legitimate his child through
adrogatio. ==Imperial succession==